None. :) Honey is basically 5:1 sugar to water. So if you feed 2:1 syrup, they have to remove at least half of the water to get it close to 5:1. Try it this way. For every 6 pounds of capped stores, you have to feed 5 pounds of sugar in your syrup. The water is not relevant except for the work required to dry it.

There are few threads on corn syrup. Commercial beekeepers (but not only) use corn syrup since it is cheap. It is as far as possible to what bees would use; i believe (only personal belief shared by many others) it is un-natural and harmful to bees. They will not overwinter as well on HFCS as on honey, with sugar somewhere in between. The best is not to have to feed, leaving enough honey to the hive, robbing the strong to give the weak (w/out endangering the strong), storing honey frames for later... Ultimately it is almost a "philosophical" question, your philosophy of hive management.

So you would be pretty close to a lb of storage vs a lb of sugar based off of energy consumption

Yes, assuming the bees are drawing new wax to store the syrup in. If you have existing drawn comb you would get more than 1 lb of stores. It is not likely that the bees are drawing much wax this time of year. More likely that they will backfill the broodnest.